Ontrol agents and diphenolic crosslinking agents powdered coating composition of unsaturated glycidyl copolymer flow c

ABSTRACT

Powder coating compositions are disclosed. In general, individual powder coating compositions are a mixture of the following materials. A copolymer of glycidyl methacrylate and an ethylenically unsaturated compound is formed in such proportions as to obtain a copolymer with a glass transition temperature in the range of 40*C to 90*C and a molecular weight (Mn) in the range of 2500 to 8500. The glycidyl methacrylate is present in the copolymer from at least about 8 percent by weight to no more than about 25 percent by weight. Another material of the coating composition is a cross linking agent formed of a diphenol having a molecular weight in the range of about 110 to 550, the diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer. A third material used in forming the powder coating mixture is a flow control agent which forms at least 0.05 percent by weight of the mixture. The flow control agent is a polymer having a molecular weight (Mn) of at least 1000. The flow control agent also has, at the baking temperature of the powder coating composition, a lower surface tension than the surface tension of the copolymer.

ilted States Patent 1191 Labana et al.

i 3,758,634 Sept. 11, 1973 1 1 POWDERED COATING COMPOSITION OF.

UNSATURATED GLYCIDYL COPOLYMER, FLOW CONTROL AGENTS AND DIPHENOLIC CROSSLINKING AGENTS [75] Inventors: Santokh S. Labana, Dearborn Heights; Seymour Newman, Southfield, both of Mich.

[73] Assignee: Ford Motor Company, Dearborn,

Mich.

[22] Filed: Aug. 16, 1971 [21] Appl. No.: 172,228

[52] US. Cl. 260/836, 117/93.4 R, 117/126 GE,

117/126 GR, 117/132 BE, 260/37 EP, 260/41 R, 260/41 A, 260/41 B, 260/41 C, 260/830,

Primary Examiner-Paul Lieberman Attorney-Keith L. Zerschling and William E.

Powder coating compositions are disclosed. In general, individual powder coating compositions are a mixture of the following materials. A copolymer of glycidyl methacrylate and an ethylenically unsaturated compound is formed in such proportions as to obtain a copolymer with a glass transition temperature in the range of 40C to 90C and a molecular weight (171,) in the range of 2500 to 8500. The glycidyl methacrylate is present in the copolymer from at least about 8 percent by weight to no more than about 25 percent by weight; Another material of the coating composition is across linking agent formed of a diphenol having a molecular weight in the range of about 110 to 550, the diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer. A third material used in forming the powder coating mixture is a flow control agent which forms at least 0.05 percent by weight of the mixture. The flow control agent is a polymer having a molecular weight (M of at least 1000. The flow control agent also has, at the baking temperature of the powder coating composition, a lower surface tension than the surface tension of the copolymer.

3] Claims No Drawings BACKGROUND OF THE INVENTION Powder coating compositions for use in the painting of surfaces are extremely desirable. Such coating compositions are desirable because they eliminate the solvents utilized in liquid paint systems as, for example, the paint system shown in US. Pat. No. 2,857,354, issued Oct. 21, 1958. A powder coating paint composition is curable by heat in a manner that little, if any, volatile material is given off to the surrounding environment. This is substantially different from a liquid paint system as the liquid paint vehicle must be volatilized during the drying of the paint. Volatilization of the liquid vehicle, of course, carries such vaporized material into the surrounding ambient.

This invention is directed to powder coating compositions which are suitable for finishing surfaces of articles with a protective and decorative coating. The coatings produced by the compositions of this invention are comparable on all terms with the coatings produced by the prior art liquid paint systems. The liquid paint system disclosed in U'.S. Pat. No. 2,857,354 is apparently similar but, in reality, substantially different than the powder coating compositions of thisinvention. -A full discussion of these differences is set forth in the last portion of this specification.

SUMMARY OF THE INVENTION tion greater than 1 minute at the baking temperature of the composition. The coating composition may also use therein a pigment which forms from about 6 percent by weight to about 35 percent by weight of the total mixture depending on the pigment selected and the gloss required for the baked coating. The powder coating composition may also include a small weight percentage of an antistatic agent.

This invention is directed to powder coating compositions and, more particularly, to powder coating compositions which are curable by heat, have a longer shelf life, are non caking, are less corrosive to metal equipment, and are better for use with metallic aluminum pigment than powder coatings using only dicarboxylic acids as cross linking agents. When properly baked and cured, the coatings from these powders possess good gloss, impact propertiesand solvent resistance. A powder coating composition formed in accordance with the teachings of this invention comprises an intimate mixture of several materials. A first material of the mixture is a copolymer of glycidyl methacrylate and an ethylenically unsaturated compound in such proportions as to obtain a copolymer with a glass transition temperature in the range of 40C to 90Cand with a molecular weight (FL) in the range of 2,500 to 8,500. The glycidyl methacrylate is presentin the copolymer from at least about 8 percent by weight to no more than about 25 percent by weight. Another material of the mixture is a cross linking agent formed of a diphenol having a molecular weight in the range of about l 10 to 550, the diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy groupin the copolymer. Another material of the mixture is a flow control agent which forms-at least 0.05 percent'by weight of the mixture. This flow. control agent is a polymer having a molecular weight (FL) of atleast 1,000. The flow control agent also has, at the baking temperature of the powder coating composition, a lower'surface tension than the surface tension of the copolymer.

' In greater detail, a powder coating composition formed in accordance with the teachings of this invention includes a small weight percent of a catalyst which produces a gel time tor the powder-coating composi- The preferred ranges for individual contents of the materials for the powder coating compositions described above is as follows. The glycidyl methacrylate which forms a portion of the copolymer in the mixture should be present in the copolymer in the range of at least 8 percent by weight to no more than 25 percent by weight. A desirable range of glycidyl methacrylate in the copolymer is at least 12 percent by weight to no more than 18 percent by weight with the most desirable copolymer containing approximately 15 percent by weight of the glycidyl methacrylate. Also, the preferred glass transition temperature for the copolymer is in the range of 50C to C with a molecular weight (M2) in the range of 3,000 to 6,500. The most desirable glass transition temperature for the copolymer is 60C to With respect to the flow control agents used in the powder coating mixture, an individual agent selected fora mixture may be an acrylic polymer having a glass transition temperature below the glass transistion temperature of the mixtures copolymer. Preferred acrylic polymers which may be used for the flow control agent are polylauryl acrylate, polybutyl acrylate, poly (2- ethylhexyl acrylate), polyl'auryl, methacrylate and polyisodecyl methacrylate; t

The flow control agent may alsobe a fluorinated polymer having a surface tension, at the baking temperature of the powder, lower than that of the copolymer utilized in the mixture. Preferred flow control agents, if the agent is a fluorinated polymer are esters of polyethyleneglycol or polypropyleneglycol and fluorinated fatty acids. For example, an ester of polyethyleneglycol of molecular weight of over 2,500 and perfluoro octanoie acid is a useful flow control agent.

ln -addition to the glycidyl methacrylate monome used in all copolymer formingmixtures, other monomers which may be used are methyl methacrylate, butyl methacrylate, butyl acrylate, ethyl acrylate, 2-

ethylhexyl acrylate, styrene, alpha methyl styrene, ac-

A small weight percentage of a catalyst is added to the powder coating composition in order to increase the cross linking rate of the powder coating composition at the baking temperature thereof. In preference, the catalyst produces a gel time for the powder coating composition of at least 1 minute but no greater than 40 minutes. The preferred catalyst is one which produces a gel time of at least 1 minute but no greater than minutes. in general, the catalyst is present in the range of from 0.05 percent by weight to 1 percent by weight of the weight of the mixture. The most desirable gel time produced by the catalyst is in a time range of from about 3 minutes to about 10 minutes. These catalyst gel times are at baking temperatures for the powder coating compositions in the range of 130C to 200C.

The powder coating compositions of this invention may also contain from about 6 percent by weight to about 35 percent by weight of a pigment. The various pigments already known in the art may be employed in the powder coating compositions. The pigments are generally selected for color, appearance or corrosion protection properties.

A small weight percent of an antistatic agent may also be employed in the powder coating composition. For example, 0.05 percent by weight to 0.5 percent by weight of the powder coating composition may be an antistatic agent so that the coating may be applied in an electrostatic spraying operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT A general discussion of the various materials which may be employed in the powder coating compositions of this invention will be set forth below. Also, a plurality of examples will be employed to show the manner in which various, individual, powder coating compositions, which fall within the scope of this invention, are prepared and utilized.

The principle material in individual powder coating compositions is a copolymer formed from glycidyl methacrylate and an ethylenically unsaturated monomer in such proportions as to obtain a copolymer with a glass transition temperature in t he range of 407C to 90C and a molecular weight (M,,) in the range of 2,500 to 8,500. The ethylenically unsaturated monomer employed to form the copolymer is any one, or a mixture of the many different monomers known to those skilled in the art. In forming the copolymer, the glycidylmethacrylate is present in the final copolymer from at least about 8% by weight to no more than about 25 percent by weight. The balance of the weight of the copolymer is formed from the ethylenically unsaturated monomers.

The preferred ethylenically unsaturated monomers which are employed to form the copolymer with the glycidyl methacrylate are methyl methacrylate, butyl methacrylate, butyl acrylate, ethyl acrylate, 2- ethylhexyl acrylate. Suitable modifying monomers such as styrene, alpha methyl styrene, acrylonitrile, and methacrylonitrile can be used with the preferred monomers. When used, a modifying monomer is present in the copolymer from a weight percent of about 0 percent by weight to no more than about 35 percent by weight. Thus, when the preferred ethylenically unsaturated monomers are used with glycidyl methacrylate to form the copolymer, the glycidyl methacrylate is present in the copolymer from 8 percent by weight to about 25 percent by weight, the modifying monomer is present from about 0 percent by weight to no more than about 35 percent by weight, and the preferred monomer is present from about 92 percent by weight to about 40 percent by weight.

in accordance with detailed teachings of this invention, the copolymer for the powder coating composition is formed from glycidyl methacrylate, methyl methacrylate, and butyl methacrylate. In this instance, the glycidyl methacrylate is present in the copolymer from about 8 percent by weight to no more than about 25 percent by weight, the methyl methacrylate is present in the copolymer from about 25 percent by weight to about 60 percent by weight, and the balance of the copolymer is butyl methacrylate.

The copolymers of glycidyl methacrylate can be prepared by a variety of methods. Generally, a free radical initiator is needed to induce polymerization reaction. A large number of free radical initiators are known in the art. These include benzoyl peroxide, lauryl peroxide, t-butyl-hydroxyperoxide, acetylcyclohexane sulfonyl peroxide, di-isobutyryl peroxide, di-(2-ethylhexyl) peroxydicarbonate, di-isopropyl peroxydicarbonate, t-butylperoxypivalate, decanoyl peroxide, azobis (2- methylpropionitrile), etc. The polymerization is preferably carried out in solution using a solvent in which the glycidyl methacrylate copolymer is soluble. Toluene, xylene, dioxane, butanone, etc., are suitable solvents for polymerization. if the glycidyl methacrylate copolymer is prepared in solution, the solid copolymer can be obtained by evaporating the solvent under vacuum or spray. drying techniques. Alternatively, the copolymer can be precipitated by pouring the solution at a slow rate into a non-solvent liquid such as hexane, octane or water under a suitable agitation condition at a slow rate. The copolymer thus obtained should be further dried sothat it contains less than three percent of the materials that volatilize at the temperatures used for baking the coatings Glycidyl methacrylate copolymers can also be prepared by emulsion polymerization, suspension poly merization, bulk polymerization or their suitable combinations. In these methods of preparing glycidyl methacrylate copolymers, chain transfer agents may be required to control the molecular weight of vthe copolymer to a desired range. The solid eopolymers obtained by 'these methods must also be dried to containless than three-percent of the materials that volatilize at the temperatures used for baking the coatings.

For powder coating. applications, molecular weight and molecular weight-distribution-of the'glycidyl methacrylate copolymer is important; C-opolymer of average molecular weight (M in the range of 2,500 to 8,500 are suitable. These copolymers, however, must not contain significant amount of higher molecular weight fractions. No more than 2 percent of thecopolymer can be of molecular weight greater than 20,000. The molecular weight distribution'as measured by the ratio of weight average molecular weight tonumber average molecular weight (M /m") Should be in the range of 1.6 to 2 l. The preferred range of molecular weightdistribution is in the range of 1.7 to 1.8.-

Another one of the materials of individual ones of the powder coating compositions of this invention is a cross linking agent formed of a diphenol having a molecularv weight in the range of about to 550, the diphenol being present in the amount of 0.8 to L1 phenolic hydroxyl groups for each epoxy group in the copolymer. In still greater detail, the most desirable diphenol is a diphenol selected from the group consisting of Bisphenol A, dihydroxydiphenyl sulfone, 1,1 bis (4- hydroxyphenyl) cyclohexane, 2,2'-biphenol, 4,4- biphenol, 1,3-dihydroxynaphthalene, bis (2- hydroxyphenyl) methane, 4,4 dihydroxydiphenyl sulfide, 4-4 dihydroxydiphenyl oxide, bis (4 hydroxyphenyl) methane and 2-2'-bis (4- hydroxyphenyl) butane.

A flow control agent is also included in forming each individual one of the powder coating compositions of this invention. The flow control agent forms at least 0.05 percent by weight of an individual powder coating. The flow control agent generally does not exceed about 4 percent by weight of any individual powder coating composition. In general, the flow control agent is a polymer having a molecular weight (fi of at least 1,000. Further, the flow control agent has, at the baking temperature of the powder coating composition, a lower surface tension than the surface tension of the copolymer employed in forming the composition.

One type of material which is used as a flow control agent in the powder coating compositions isan acrylic polymer having a glass transition temperature below the glass transition temperature of the compositions copolymer. Some acrylic polymers which are .preferred as flow control agents are polylauryl acrylate, polybutyl acrylate and poly (2-ethylhexyl acrylate). Acrylic polymers to be used as flow control agents can be prepared by polymerization of the acrylate or methacrylate monomers in bulk or in suitable solvent using well known free radical initiators. The amount of the initiator and the polymerization conditions arechosen so that polymer formed has molecular weight (ii/1 above 1,000. The preferred molecular weight range of the acrylate polymer is above 5,000. The most preferred range of the acrylate polymer is 6,000 to 20,000.

Although polymeric acrylate flow control agents are preferred, fluorinated polymers have been found to act as flow control agents for the powder coating compositions. Such fluorinated polymers are esters of polyethyleneglycol or polypropyleneglycol andfluorinated fatty acids. Esters of polyethyleneglycol. of molecular weight (fi of over 2,500 and perfluoro octanoic acid are useful as flow control agents for the compositions of this invention.

The individual powder coating compositions of this invention each contain a small,;effecti ve, weight percentage of a catalyst. In general, the catalyst is present in an individual composition in a range from 0.05 percent by weight to 1.0 percent by weight. The catalyst is selected to produce a gel time for the powder coating composition greater than at least 1 minute atthe baking temperature of the composition. A suitable catalyst is also one which will producea gel time that does not nium chloride (bromide or iodide), tetramethyl ammonium chloride (bromide or iodide), trimethylbenzyl ammonium chloride, dodecyl dimethyl (2- phenoxyethyl) ammonium bromide and diethyl (2- hydroxy ethyl) methyl ammonium bromide. Suitable catalysts of the imidazole type include: 2-methyl-4- ethyl imidazole, 2-methyl imidazole, imidazole, 2-[(N- benzylanilino) methyl] -2-imidazoline phosphate, and 2-benzyl-2-imidazoline hydrochloride. Suitable tertiary amine catalysts for the powder coating compositions of this invention include: tri-ethylenediamine, N,N-diethylcyclohexylamine, and N-methyl morpholine. The metal salts of organic carboxylic acid which are catalyst for the powder coatings of this invention include, but are not limited to: stannous octoate, zinc naphthenate, cobalt naphthenate, zinc octoate, stannous Z-ethylhexoate, phenylmercuric propionate, lead neodecanoate, dibutyl tin dilaurate and lithium benzoate.

The catalyst used in an individual powder coating composition is generally solid at room temperature and has a melting point of from C to 200C. As previ ously specified, the catalyst is present in a powder coating composition from 0.05 percent by weight to 1.0 percent by weight of the total weight of the powder composition. Further, the catalyst produces a gel time of at least 1 minute and no greater than 40 minutes. Generally, the preferred gel time of the composition is in the range of from 1 minute to approximately 10 minutes at the baking temperature of the composition.

included in a range from 0.05 percent to 1.0 percent by weight of the total powder composition. Suitable antistatic agents include, but are not limited to, tetralkylammonium salts'as discussed previously and which also serve as catalysts. Other suitable antistatic agents include: alkyl-poly (ethyleneoxy) phosphates as, for example, dibutylpoly (ethyleneoxy) phosphateor alkylarylpoly (ethyleneoxy)-phosphates as, for example,

ethyl ,benzyl poly I (ethyleneoxy) phosphate; polyethyleneimine', poly (Z-vinyl pyrollidone), pyridiniun chloride, poly(vinyl pyridinium chloride), polyvinyl-ab 9 echo] or inorganicsalts.

- ing: basic lead silico chromate 30 percent by weight exceed 40 minutes; As used herein, the gel time of a salts, imidazole typecatalysts, tertiary amines and metal salts oforganic carboxylic acids. The tetralkylammonium salts catalysts include the folling: tetrabutyl ammonium bromide, tetrabutyl ammonium chloride, tetrabutyl ammonium iodide, tetraethyl ammo- (Orange), titanium dioxide 30 percent by weight (white); titanium dioxide 15 percent by weight plus ultra marine blue 10 percent by weight (blue); phthalocyanine blue 7 percent by weight plus titanium dioxide 10 percent by weight (blue); phthalocyanine green 7 percent by weight plus titanium dioxide 10 percent by weight (green); ferrite yellow 7 percent by weight plus titanium dioxide 10 percent by weight (yellow); carbon black pigment 6 percent by weight (black); black iron oxide 10 percent by weight (black); chromium green oxide 8 percent by weight plus titanium dioxide 10 percent by weight (green); quindo red percent by weight plus titanium dioxide 16 percent by weight (red); and iron oxide transparent orange pigment 10 percent by weight (orange). Metallic aluminum pigment may also be included to give the baked coating a metallic look. Such aluminum pigments is included up to 10 percent by weight. 7

Having generally described the various materials which are employed in formulating the powder coating compositions of this invention, a plurality of examples will be set forth to illustrate various individual powder coating compositions.

EXAMPLE 1 The monomers, glycidyl methacrylate percent by weight, methyl methacrylate 45 percent by weight and butyl methacrylate 40 percent by weight are mixed together. Three weight percent of a catalyst 2,2'-azobis- (Z-methylpropionitrile) (AIBN) is dissolved in the monomer mixture. The mixture is slowly added to refluxing toluene (100 parts) which is stirred vigorously under a nitrogen atmosphere. A condenser is provided at the top of the toluene container to condense the toluene vapors and return them to the container. The monomer mixture is added through a regulating valve and the rate of addition is controlled to maintain a reflux temperature (109C-1 12C) with only a small fraction of heat supplied from an external heater. After the addition of the monomer mixture is complete, the refluxing is maintained by external heat source for 3 additional hours.

The solution is poured into shallow stainless steel trays. These trays are placed in a vacuum oven and the solvent evaporated therefrom. As the solvent is removed, the copolymer solution becomes more concentrated. The temperature of the vacuum oven is raised to about 110C. Drying is continued until the solvent content of the copolymer is below 3 percent. The trays are cooled and the copolymer collected and ground to pass through mesh screen. The copolymer has a glass transition temperature of 53C and a molecular weight m of 4000.

One hundred parts by weight of the ground copolymer are mixed with the following materials:

Bisphenol A 12.0 parts Tetrabutyl ammonium bromide 0.2 part Polylauryl actylate (M,,=l0,000) 0.5 part Titanium dioxide I parts Thematerials are mixed together in a ball mill for 2 hours. The mixture is milled rolled at 85C to 90C for 5 minutes. The solid obtained is ground in a ball mill to pass through a 140 mesh screen.

The resulting powder thus obtained is a powder coating composition of the invention. The powder is sprayed on an electrically grounded, steel panel by using electrostatic powder spray gun operating at 50 KV charging voltage. After spraying, the panel is heated at 175C for 20 minutes;

The coating obtained on the panel has good adhesion to the steel panel and good impact strength. The coating also is applied to and has good adhesion on panels of glass, brass, zinc, aluminum, copper, and bronze. The coating obtained is not solublein toluene, gasoline, butanone or methanol.

EXAMPLE 2 The procedure of Example I is repeated. The formation of the copolymer, however, begins with a monomer mixture having glycidyl methacrylate 8 percent by weight, methyl methacrylate 52 percent by weight and butyl methacrylate 40 percent by weight. Three weight percent of the catalyst AIBN is employed. When the procedure of Example I is followed, the resulting copolymer has a glass transition temperature of 58C and a molecular weight of 4,000.

One hundred parts of the copolymer produced is mixed with the same additional ingredients set forth in Example 1, except using 6.4 parts Bisphenol A. The quality of the painted panels obtained after application of the powder coating to various materials is about the same as achieved in Example 1.

EXAMPLE 3 A monomer mixture having the following composition is prepared: glycidyl methacrylate .12 percent by weight, methyl methacrylate 48 percent by weight, and

butyl methacrylate 40 percent by weight. The monomer mixture is processed in the same manner as described in Example 1 with 3 percent by weight of the catalyst AIBN employed. The resulting copolymer has a glass transition temperature of 56C and a molecular weight of 4,000. parts of the copolymer produced is mixed with the same additional ingredients described in Example 1, except 10.5 parts dihydroxydiphenyl sulfone are used.

The powder coating composition obtained by following the process steps set forth in Example 1 is applied to test panels in the same manner as described in Example l. The coating is baked at a temperature of C for 30 minutes. The coating obtained has good adhesion to steel, glass, brass, zinc, aluminum, copper and bronze.

EXAMPLE 4 A monomer mixture having the following composition is prepared: glycidyl methacrylate 20 percent by weight, methyl methacrylate 40 percent by weight and butyl methacrylate 40'percent by weight. A copolymer is formed from this monomer mixture in accordance with the same procedure as is outlined in Example 1. In this case, 1 percent by weight of the catalyst AIBN is added. The copolymer produced has a glass transitiontemperature of 5l"C and a molecular weight. of

The ground polymer (100 parts by. weight) is added to the following materials:

Bisphenol A 'l7.5 parts Tetrabut lammoniugrehloride 0.! part Polybuty ecrylate (M.=9000) 4 parts Titanium dioxide lS'parts Transparent blue 4 parts Metallic aluminum flakes 4 parts EXAMPLE Dihydroxydiphenyl sulfone 19.8 pans 2-methyl-4-ethylimidazole 0.05 part Dibutyl poly (ethyleneoxy) phosphate 0.05 part Polyisododecyl methacrylate 4 parts Titanium dioxide parts Phthalocyanine blue 7 parts A powder coating composition is obtained by following the process steps set forth in Example 1. The coating composition is applied to a series of test panels and baked at the temperature of and for the same time as Example 4. The coating obtained on the various test panels is of poor quality with respect to its adhesion, appearance and impact characteristics.

EXAMPLE 6 A monomer mixture having the following composition is prepared: glycidyl methacrylate percent by weight, butyl acrylate percent by weight and methyl methacrylate65 percent by weight. The monomer is reacted as set forth in Example 1 in order to produce a copolymer. Four percent by'weight of the catalyst AIBN is employed in reacting the monomer mixture to form the copolymer. The copolymer has a glass transition temperature of 65C and a molecular weight of 3,000. I

One hundred parts by weight of the copolymer obtained is added to the following materials:

2,2'- bis (4-hydroxyphenyl) butane 12.7 parts Triethylene diamine 0.1 part Tetraethylamtnonium cfloride 0 5 part Polyaurylmethacrylate (M,. 6000) 2 Phthaloycanine green a 7 parts Titanium dioxide 10 parts The above described materials are processed as described in Example 1 in order to produce a powder coating composition. The powder coating composition is applied to test panels as described in Example 1 and bakedlon the panels'at a temperature of 150C for- 15 minutes. I

The coating obtained has good adhesion to steel, glass, brass, zinc, aluminum, copper and bronze and .is insoluble in toluene, gasoline, methanol and butanone.

EXAMPLE 7 A monomer mixture having the following composition is prepared: glycidyl methacrylate 15 percent by weight, methyl methacrylate 50 percent by, weight and styrene percent by weight. The monomers are reacted in accordance with the procedure set forth in Example 1 with 3 percent by weight of the catalyst AIBN being utilized. The resulting ground copolymer hasa molecular weight of 4,500 and a glass transition temperature of 90C.

One hundred parts by weight of the copolymer obtained is added to the following materials:

Dihydroxydiphenyl sulfone 13.2 parts Tetramethylammonium chloride 1 part Poly(2-ethylhexyl acrylate) 2 pans Ferrite yellow 7 parts Titanium dioxide 10 parts This mixture is processed as described in Example 1 in order to form a powder coating composition. The powder coating composition is applied to test panels as described in Example 1. The panels are baked at a temperature of 180C for 5 minutes. The adhesion quality of the powder coating after baking on the various test panels is good. The coating on each panel possesses goodsolvent and scratch resistance.

EXAMPLE 8 A monomer mixture having the following composition is formed: glycidyl methacrylate 18 percent by weight, ethyl acrylate 20 percent by weight, methyl 'methacrylate 40 percent by weight, vinyl chloride 22 percent by weight. The monomer mixture is polymerized by using 2 weight percent of AIBN as the initiator.

. One hundred parts of the ground copolymer obtained is added to the following materials:

Bia(2-hydroxyphenyl)methane 10.4 parts Trimethyl benzyl ammonium chloride 0.1 part Poly(2-ethylhexyl acrylate)(M,,=l 1,000) 2 parts Carbon black 6 parts The above materials are mixed and processed as set forth in Example 1. The resulting powder coating composition is applied to test panels as specified in Example 1. The coating composition is baked at 170C for l5 mi'nutes..All the painted panels exhibit good adhesion and solvent resistant properties.

EXAMPLE 9 A monomer mixture having the following composition is formed: glycidyl methacrylate 15 percent by weight, methyl methacrylate 30 percent by weight, isobutyl acrylate 25 percent by weight, alpha methyl styrene 115 pe'rcentby weight and methacrylonitrile; 15

' percent by weight. The monomer mixture is'reac 't'edin the same manner as described in Example 1. Three percent' of the catalyst AIBN is employed. The resulting copolymer has a glass transition temperature of 46C and a molecular weightof 4,500.

One hundred parts of the ground copolymer obtained is added to thefollowing materials:

Tetrabrornobiaphenol A. I 29.0 patts -Dodecyldirnethyl (Z-phenoxy-ethyl) 0.5 part gmlmopilim brclimidle m oyet yenegycope uoro 2 arts octonoate(M.-'3400) p 10 parts Black iron oxide :The mixture so formed is processed-as described in Example 1 to produce apowder coating composition.

This powder coating composition is applied to test panels as it is described in Example 1. The coated panels areba'ke'd at C for 15 minutes..The coating on each panel has good adhesion and solvent resistance.

EXAMPLE 10 A monomer mixture having the following composition is prepared; glycidyl methacrylate 5 percentby weight, methyl metha'crylateSS percent by weight, and

butyl methacrylate 40 percent by weight. The monomer mixture is reacted as described in Example 1 with 6 percent by weight of the catalyst AlBN. The resulting copolymer has a glass transition temperature of 55C and a molecular weight of 3,000.

One hundred parts by weight of the ground copolymer is mixed with the following materials:

Bisphenol A 4.0 parts Tetraethylammonium bromide 1 part Ethyl benzyl(ethyleneoxy) phosphate pans Poly(2-ethylhexyl acrylate) 0.4 part Chromium green oxide 8 parts Titanium dioxide 10 parts The above mixture is processed as described in Example 1 to produce a powder coating composition. The powder coating composition is applied to a plurality of test panels. The panels are baked at a temperature of 170C for minutes. The adhesion to the test panels of the powder coating material is poor and coating has a tendency to chip and crack.

EXAMPLE 1 1 Bis (4-hydroxyphenyl) methane 8.4 parts Stannous octoate 0.5 part Tetraethylamrnonium bromide 0.05 part Polyethylengglycol perfluoro 2 parts octonoate (M,,=3500) Quindo red 4 parts Metallic aluminum flakes 4 parts The mixture above described is processed as set forth in Example 1 to produce a powder coating composition. The powder coating composition is applied to test panels as described in Example 1. The panels are baked at 150C for 20 minutes. The adhesion to the panels of thepowder coating is good, each of the coating possesses good solvent resistance and has a metallic appearance.

EXAMPLE 12 'A monomer mixture having the following composition is prepared: glycidyl methacrylate 22 percent by weight, n-hexyl methacrylate 20 percent by weight, butyl methacrylate 25 percent by weight and acrylonitrile 33 percent by weight. A copolymer is formed from this monomer mixture in accordance with the same procedure as is outlined in Example 1. In this case, 1.5 percent by weight of the catalyst AlBN is added. The copolymer produced has a glass transition temperature of 40C and a molecular weight of 7,500.

The ground copolymer (100 parts by weight) is added to the following materials:

2-2'-bia(4-hydroxyphenyl butane 18.7 parts Zinc octoate 0.8 part Tetrabut lammonium iodide 1.0 part Polybuty acrylate 2.0 parts iron oxide transparent orange 4 parts Metallic aluminum flakes 4 parts The above ingredients are mixed together and processed in accordance with the procedure of Example 1 to obtain a powder coating composition. The powder coating composition is sprayed on various test panels of steel, glass, brass, zinc, aluminum, copper and bronze. The coating obtained on each test panel after curing of the powder coating composition at a temperature of 140C for 20 minutes is of good quality, has a metallic appearance, and is solvent and scratch resistant.

EXAMPLE 13 A monomer mixture having the following composition is prepared: glycidyl methacrylate 10 percent by weight, methyl methacrylate 45 percent by weight, butyl methacrylate 35 percent by weight-and vinyl acetate 10 percent by weight. A copolymer is formed from this monomer mixture in accordance with the same procedure as is outlined in Example 1. In this case, 3 percent by weight of the catalyst AlBN is added.

The ground copolymer (100 parts by weight) is added to the following materials:

44' dihydroxyphenyl oxide 7.1 parts Tetrabutylammonium bromide 2 parts Poly (Z-ethylhexyl acrylate) 3.5 parts Carbon black 6 parts The above ingredients are mixed together and processed in accordance with the procedure of Example 1 I to obtain a powder coating composition. The powder coating composition is sprayed on various test panels. The coating obtained on each test panel after curing of the powder coating composition at a temperature of 160C for 10 minutes is of good quality. Also, the coating obtained on each test panel is insoluble in toluene, gasoline, methanol and butanone.

EXAMPLE 14 A monomer mixturehaving the following composition is prepared: glycidyl methacrylate 8 percentby weight, methyl methacrylate 52 percent by weight and isobutyl methacrylate 40 percent by weight; A copolymer is formed from this monomer mixture in accordance with the same procedure asis outlined in Exam: ple 1. In this case, 5 percent-by weight of the catalyst AIBN is added. The copolymer produced has a glass transitiontemperature of C and a molecular weight of 3,200.

The ground copolymer parts. by weight) is added to the following materials:

2,2'-biphenol 5.2 parts Tetrabutylammonium' bromide 2 parts Polylauryl acrylate 4 parts Titanium dioxide 30 parts The above ingredients are mixed together and processed in accordance with the procedure of Example 1 to obtain a powder coating composition. The powder coating composition is sprayed on various test panels of steel, brass, glass, zinc, aluminum, copper and bronze. The coating obtained on each test panel after curing of the powder coating composition at a temperature of C for 10 minutes is of good quality and is solvent and scratch resistant.

EXAMPLE l5 A monomer mixture having the following composition is prepared: glycidyl methacrylate 10 percent by weight, methyl methacrylate 67 percent by weight, and

n-butyl methacrylate 23 percent by weight. A copolymer is formed fromthis monomer mixture in accordance with the procedure as is outlined in Example 1. in this case, 4 percent by weight of the catalystAlBN is added. The copolymer produced has a glass transition temperature of 73C and a molecular weight of 3,000.

The ground copolymer (100 parts by weight) is added to the following materials:

1,1 bis(4-hydroxyphenyl) cyclohexane 9.45 parts Tetrabutylammonium chloride 0.7 part Polybutyl acrylate 2 parts Titanium dioxide 30 parts The above ingredients are mixed together and processed in accordance with the procedure of Example l to obtain a powder coating composition. The powder coating composition is sprayed on various test panels. The coating obtained on each test panel after curing of the powder-coating composition at a temperature of 180C for 15 minutes is of good quality. Also, each of the test panels coatings is resistant to and insoluble in toluene, gasoline, methanol and butanone.

EXAMPLE 16 A monomer mixture having the following composition is prepared: glycidyl methacrylate 15 percent by weight, methyl methacrylate 32 percent by weight, ethyl acrylate 15 percent by weight, isobutyl acrylate 8 percent by weight, and styrene 30 percent by weight. A copolymer is formed from this monomer'mixture in accordance with the same procedure as is outlined in Example 1. in this case, ,3 percent by weight of the catalyst AIBN is-added.

The ground copolymer (100 parts by weight) is added to the following materials:

4,4dihydroxydiphenyl sulfide 11.5 parts Tetraethylammonium bromide 1 part Polyisodecyl methacrylate(M.-5000) 1.5 parts Titanium dioxide H 30 parts The above ingredients are mixed together and processed in accordance withthe procedure of Example 1 to obtain a powder coating composition. The powder coating composition is'sprayed on various test panels of steel, glass, brass, zinc, 'aluminum, copper and bronze. The coatings obtained on each test panel after curing 4,4'-biphenol The above ingredients are mixed together and processed in accordance with the procedure of Example 1 to obtain a powder coating composition. The powder coating composition is sprayed on various test panels of steel, glass, brass, zinc, aluminum, copper and bronze. The coating obtained on each test panel after curing of the powder composition at a temperature of 170C for 20 minutes is of good quality and resistant to the aforementioned solvents.

EXAMPLE [8 13.7 parts Tetraethylammonium bromide 0.5 part Polylauryl acrylate 1.0 parts Titanium dioxide 30 parts The above ingredients are mixed together and processed in accordance withthe'procedure of Example 1 to' obtain a powder coating composition. The powder coating composition is sprayed on various test panels of steel, glass, brass, zinc, aluminum, copper and bronze. The coating obtained on each test panel after curing of the powder coating compositionat a temperature of 180C for 10 minutes is of good quality and'is resistan to the aforementioned solvents.

EXAMPLE 19 A monomer mixture having the following composition is prepared: glycidyl methacrylate 15 percent by weight, butyl methacrylate 15 percent by weight, ethyl acrylate 15' percent by weight, methyl methacrylate 30 percent by weight and styrene 25 percent by weight. A copolymer is formed from this monomer mixture in acco'rdance with the same procedure as is outlined in E1:-

of the powder coating composition at a temperature of 140C for 15 minutes is of good quality and has good adhesion characteristics. The powder coating composition on each panel is-resistant to the solvents previously mentioned. I

EXAMPLE 17 A monomer mixture having the following composition is prepared: glycidyl methacrylate 15 percent by weight, methyl methacrylate 40 percent by weight, 2- ethylhexyl acrylate 15 percent by weight, alpha methyl styrene 20 percent by weight, and acrylonitrile 10 percent by weight. A copolymer is formedfrom this monomer mixture using 4 percent by weight of the catalyst AIBN. v e

The ground copolymer (100 parts by weight) is added to the following materials:

l.3-dihydroxynaphthalene 9.2 parts Tetraethylammonium bromide 0.4 part Poly(2-ethylhexyl acrylate 2 parts Titanium dioxide 30 parts ample l. In this case, 4 percent by weight AlBN istidded. 1 The ground copolymer parts by weight) is added to the following materials: 1 I

of the catalyst Dihydroxydiphenyl Iulfone 13.8 parts Tetraethylammonium bromide 1.0 parts Polylauryl-acrylate 0.5 port 30 parts Titanium diOXldG:

The above'ingredients are mixed together and processed in accordance with the procedure of Example l to obtain a powder coating composition. The powder coating composition is sprayed on various test panels of steel, glass, brass, zinc, aluminum, copper and bronze. The coatingobtained oneach test panel after curing of the powder coating composition at a temperature of C for 30 minutes is of good quality and resistant to the aforementioned solvents.

EXAMPLE 2 0" A monomer mixture having the following composi- HEM-hydroxyphenyl) methane 100 parts Tetraethylammonium bromide 0.5 part Polylauryl acrylate 2.5 parts Titanium dioxide 30 parts The above ingredients are mixed together and processed in accordance with the procedure of Example 1 to obtain a powder coating composition. The powder coating composition is sprayed on various test panels of steel, glass, brass, zinc, aluminum, copper and bronze. The coating obtained on each test panel after curing of the powder coating composition at a temperature of 135C for 30 minutes is of good quality. Also, the coatings are resistant to and insoluble in toluene, gasoline, methanol and butanone.

The use of glycidyl methacrylate copolymers and dicarboxylic acid cross linking agents in a liquid paint system is described in U.S. Pat. No. 2,857,354. However, the powder coating compositions of this invention are substantially different than the liquid paint composition described in the examples of that patent. This difference can be best illustrated by attempting to prepare powder coating compositions by evaporating the solvents from the liquid paint systems described in the examples of the patent. Dry powders cannot be prepared from the compositions of Examples 4 and 5 of the patent. Powders prepared from the compositions of Examples l, 2, 3 and 6, when deposited on a metal panel, do not fuse together to form a film when the panels are baked at 150 to 200C for minutes. The baked coatings on test panels are not smooth, but rather, are

rough. Also, the baked coatings possess very low gloss,

and have a lack of flexibility and adhesion. It, therefore, can be concluded that compositions which are generally suitable for liquid paint systems are not necessarily suitable for powder paints by simply evaporating the solvents therefrom.

The use of a dicarboxylic acid as a cross linking agent for'glycidyl rnethacrylate terpolymers is mentioned in U.S. Pat. No. 3,058,947. In order to test thesematerials, compositions of Example VII of this patent are dried by evaporating solvents under vacuum. The materials are ground to pass through a 200 'mesh screen. Samples of the ground powder are deposited on metal panels and baked at 160C for minutes. The coatings obtained show an abundance of craters, are inferior in gloss and smoothness, and lack the impact properties described in the Example Vll. It is, therefore, concluded that there is a substantial difference in paint films produced on a panel when the coating is produced on one hand by a liquid system, and, on the other hand, by a powder system. Other, improvements specific to the powders are needed in order to obtain paints'of acceptable quality. The reason for the difference between the properties and appearance of powder coatings derived by solvent evaporation from a liquid coatingand the liquid coatings itself are not clear. It is,

however, certain that the powders obtained by drying liquid paint compositions are not useful for powder coating compositions.

There has been disclosed herein powder coating compositions which may be employed in the painting of articles. The powder coating compositions have a longer shelf life, are non-caking, are less corrosive to metal equipment, and are better for use with metallic aluminum pigment than powder coating using only dicarboxylic acidsas cross linking agents.

Many modifications of this invetion will be apparent to those skilled in the art in view of this specification. It is intended that all such modifications which fall within the scope of this invention be included within the appended claims.

We claim:

1. A powder coating composition comprising a mix.- ture of:

A. a copolymer of a glycidyl ester of a monoethylenically unsaturated acid and an ethylenically unsaturated compound in such proportions as to obtain a copolymer with a glass transition temperature in the range of 40C to C and a molecular weight (Fi in the range of 2,500 to 8,500, said glycidyl ester being present in the copolymer from at least about 8 percent byweight to no more than 25 percent by weight;

B. a diphenol having a molecular weight in the range of about to 550, said diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer; and

C. a flow control agent forming from at least 0.05 percent to about 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (Q of at least 1,000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate' esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids.

2. The powder coating composition of claim 1 further comprising: (D) a small weightpercent of a catalyst which produces a gel time for the powder coating composition greater than 1 minute at the baking temperature of the composition.

3.. The powder coating composition of claim 2 further comprising: a pigment forming from about 6 percentby weight to about 35 percent by weight of the total mixture.

4. The powder coating composition of claim 3 further comprising: a small weight percentage of an antistatic agent.

5. The powder coating composition of claim 2 wherein: said diphenol is selected fromthe group consisting ,of Bisphenol A, dihydroxy diphenyl sulfone,

1,] '-bis (4-hydroxyphenyl) cyclohexane, 2,2- biphenol, 4,4 '-biphenol, l,3-dihydroxynaphthalene, bis(Z-hydroxyphenol) methane, 4,4-

dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl.ox

ide, bis(4-hydroxyphenyl) methane, and 2,2-bis(4- hydroxyphenyl) butane.

6. A powder coating composition comprising a mixture of:

A. a copolymer of a glycidyl. ester of a monoethylenically unsaturated acid and an ethylenically unsaturated compound in such proportions as to obtain a copolymer with a glass transition temperature in the range of 50C to 80C and a molecular;

weight (WI in the range of 3,000 to 6,500, said glycidyl ester being present in the copolymer from at least about percent by weight to no more than about percent by weight;

B. a diphenol selected from the group consisting of Bisphenol A, dihydroxy diphenyl sulfone, l,l-bis (4-hydroxyphenyl) cyclohexane, 2,2'-biphenol, 4,4'-biphenol, l,3-dihydroxynaphthalene, bis (2- hydroxyphenyl) methane, 4,4'-dihydroxydiphenyl sulfide, 4,4-dihydroxydiphenyl oxide, bis (4- hydroxyphenyl) methane, and 2,2'-bis (4- hydroxyphenyl) butane, said diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer;

C. a flow control agent forming from at least about 0.05 percent to about 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (R1,) of at least 1,000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and i D. a small weight percentage of a catalyst which produces a gel time for the powder coating composiwherein: said diphenol is selected from'the group contion at the compositions baking temperature of at least 1 minute and no greater than 40 minutes.

7. The powder coating composition of claim 6. further including: a pigment forming from about 6 percent by weight to about by weight of the .total mixture.

8. The powder coating composition of claim 7 further including: a small weight percentage of an antistatic agent.

9. The powder coating, composition of'claim 6 wherein: said diphenol is selected from the group consisting of Bisphenol A, dihydroxydiphenyl sulfone, bis(2-hydroxyphenyl) methane, and .2,2'-bis(4.- hydroxyphenyl) butane.

10. A powder coating composition comprising a mixture of:

A. a copolymer of a glycidyl ester of a monoethylenically unsaturated acid and an ethylenically unsaturated compound in such proportions as to obtain a copolymer which a glass transition temperature in the rang e of C to C and with a percent to 4.0 percent by weight of the mixture,

sisting of Bisphenol A and dihydroxydiphenyl sulfone.

14. 'A powder coating composition comprising a mixture of:

A. a copolymer of a glycidyl ester of a monoethylenically unsaturated acid and (1) an ethylenically unsatured monomer selected from the group consisting of methyl methacrylate, butyl methacrylate, butyl acrylate, ethyl acrylate, and 2ethylhexyl acrylate; and (2) a modifying monomer selected from the group consisting of styrene, alpha methyl styrene, acrylonitrile and me'thacrylonitrile, in such proportions as to obtain a copolymer having a glass transition temperature in the range of 40C to C and a molecular weight (HQ in the range of 2,500

to 8,500, said glycidyl ester being present in the copolymer from at least about 8 percent by weight to no more than 25 percent by weight, said modifying monomer being present in the copolymer from 0 a percent by weight to no more than about 35 percent by weight;

B'. a diphenol having a molecular weight in the range of about to 550, said diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer;

- C. a flow control agent forming from at least 0.05 percent to 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (Q of at least i000, said flow control agent being a polymer or acopolymerselected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and

, D. a small weight percentage of a catalyst which resultsin a gel time for the powder coating composition atits bakingtemperature of at least 1 minute but no greater than 40 minutes.

15. The" powder coating composition of claim 14 wherein: a pigment'is included, which forms from-about 6 percentby weight to about 35 percent by weight of the total mixture of the powder caoting composition.

' said flow control agent being a polymer having a molecular weight 1H,.) of at least 1,000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and

16. The powder coating composition of claim 15 wherein: a small weight percentage of an antistatic agent is added.

l7. The powder coating composition of claim 14 wherein: said'diphenol is selected from the group consisting of Bisphenol A, dihydroxy diphenyl sulfone, l,1-bis(4-hydroxyphenyl) cyclohexane, 2,2'-biphenol, 4,4 -biphenol, l,S-dihydroxynaphthalene, bis(2- hydroxyphenyl) methane, 4,4-dihydroxy diphenyl sultide, 4,4'-dihydroxydiphenyl, oxide, bis- (4- hydroxyphenyl) methane, and v2,2'-bis(4- hydroxyphenyl) butane.f

18. A powder coating composition comprising a mixtureof: i v

A. a copolymer of a glycidyl ester of a monoethylenically unsaturated acid and (i) an ethylenically unsaturated monomer selected from the group consisting of methyl methacrylate, butyl methacrylate, butyl acrylate, ethyl acrylate, and 2- ethylhexyl acrylate, and (2) a modifying monomer selected from the group consisting of styrene, alpha methyl styrene, acrylonitrile and methacrylonitrile in such proportions as to obtain a copolymer having a glass transition temperature in therange of 50C to 80C and a molecular weight (R1,) in the range of 3,000 to 6,500, said glycidyl ester being present in the copolymer from at least 10 percent by weight to no more than 20 percent by weight, said modifying monomer being present in said copolymer from percent by weight to no more than about 35 percent by weight; and

B. a diphenol selected from the group consisting of Bisphenol A, dihydroxy diphenyl sulfone, 1,1- bis(4-hydroxyphenyl) cyclohexane, 2,2'-biphenol, 4,4'-biphenol, l,3-dihydroxynaphthalene, bis (2- hydroxyphenyl) methane, 4,4-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl oxide, bis(4- hydroxyphenyl) methane, and 2,2'-bis(hydroxyphenyl) butane, said diphenol being present in the amount of 0.8 to L1 phenolic hydroxy groups for each epoxy group in the copolymer;

C. a flow control agent forming from at least about 0.05 percent to 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (In of at least 1,000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and

D. a small weight percentage of a catalyst sufficient to produce a gel time for the powder coating composition at its baking temperature of at least 1 minute but no greater than 40 minutes.

19. The powder coating composition of claim 18 whereinra pigment is included which forms about 6 percent by weight to about 35 percent by weight of the total mixture of the powder coating'composition.

20. The powder coating composition of claim 19 wherein: a small weight percentage of antistatic agent is added.

21. The powder coating composition of claim 18 wherein: said diphenol is selected from the group consisting. of Bisphenol' A, dihydroxydiphenyl sulfone, bis(4-hyclroxyphenyl) methane and 2,2-bis(4- hydroxyphenyl) butane.

22. A powder coating composition comprising a mixture of:

A. a copolymer of a glycidyl ester of a monoethylenically unsaturated acid and (1) an ethylenically unsaturated monomer selected from the group consisting of methyl methacrylate, butyl methacrylate, butyl acrylate, ethyl acrylate, and 2 ethylhexyl acrylate, and (2) a modifying monomer selected from the group consisting of styrene, alpha methyl styrene, acrylonitrile and and methacrylo nitrile in such proportions as to obtain a copolymer having a glass transition temperature in the range of 60C to 70C and a molecular weight (Kl in the range of 3,000 to 4,000, said glycidyl ester being present in the copolymer from at least about 12 percent by weightto no more than 18 percent by weight, said modifying monomer being present in said copolymer from 0 percent by weight to no more than about 25 percent by weight; and

B. a diphenol selectedfrom the groupconsisting of Bisphenol A, dihydroxy diphenyl sulfone, l,l bis(4-hydroxyphenyl) cyclohexane, 2,2'-biphenol, 4,4 biphenol, 1,3-dihydroxynaphthalene, bis(2- hydroxyphenyl) methane, 4,4'-dihydroxydiphenyl sulfide, -4,4-dihydroxydiphenyl oxide, bis(4- hydroxyphenyl) methane, and 2,2-bis(4- hydroxyphenyl) butane, said'diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in ,the copolymer;

C. a flow control agent forming from at least about 0.05 percent to 4.0 percent-by weight of the mixture, said flow control agent being a polymer having a molecular mixture (i of at least 1,000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and

D. a small weight percentage of a catalyst sufficient to produce a gel time for the powder coating composition at its baking temperature of at least 1 minute but no greater than 10 minutes.

23. The powder coating composition of claim 22 wherein: a pigment is included which forms about 6 percent by weight to about 35 percent by weight of the total mixture.

24. The powdercoating composition of claim 23v wherein: a small weight percentage of an antistatic agent is added.

25. The powder coating composition of claim 22 wherein: said diphenol is selected from the group consisting of Bisphenol A, dihydroxydiphenyl sulfone,,

bis(4-hydroxyphenyl) methane and hydroxyphenyl) butane.

26. The powder coating composition of claim 23 wherein: said mixture forming said powder coating composition has a particle'size in the range from 10 microns to 100 microns.

27. The powder coating composition of claim 23 wherein: the size range of the particles forming the powder coating composition is in the range of 40 to 75 microns.

28. A powder coating composition comprising a mixmethyl styrene, acrylonitrile and methacrylonitrile in such proportions as to obtain a copolymer having a glass transition temperature in the range of 60C to C and a molecular weight (FL) in the range of 3,000 to 4,000, said glycidylester beingv present in the copolymer in the rnageof 12 to 15 percent by weight, said modifying monomerbeing present in said copolymer from 0 percent by weight to no more than 35 percent'by weight; and

B. a diphenol selected from the. group consisting of Bisphenol A and dihydroxyphenyl sulfone in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer;

C. a flow control agent forming at least about 0.05 percent to 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (Kl of at least 1,000, said flow control agent being a polymer or a copolymer selected from the group consisting of acylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and

D. a small weight percentage of a catalyst which gives to the mixture a gel time at its baking temperature of at least 3 minutes but not in excess of minutes.

29. The powder coating composition as defined in claim 28 wherein: 6 percent to 35 percent by weight of the mixture is made up of a pigment.

30. A powder coating composition comprising a mixture of: i

A. a copolymer of glycidyl methacrylate, methyl methacrylate and butyl methacrylate, said glycidyl methacrylate being present in the copolymer from about 8 percent by weight to no more than about 25 percent by weight, said methyl methacrylate being present in the copolymer from about percent by weight to about 52 percent by weight, with the balance of the copolymer being said butyl methacrylate, the copolymer having a glass transition temperature in the range of 40C to C and a molecular weight (K1,) in the range of 2,500 to 8,500; I

B. a diphenol having a molecular weight of to 550, said diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer;

C. a flow control agent forming from at least 0.05 percent to 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (3],) of at least 1,000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypro pylene glycol esters of fluorinated fatty acids; and

D. a small weight percentage of a catalyst sufficient to cause the coating composition mixture to have a gel time of at least 1 minute but no greater than 40 minutes.

31. The powder coating composition of claim 30 wherein: 6 percent to 35 percent by weight of the mixture is a pigment. v 

2. The powder coating composition of claim 1 further comprising: (D) a small weight percent of a catalyst which produces a gel time for the powder coating composition greater than 1 minute at the baking temperature of the composition.
 3. The powder coating composition of claim 2 further comprising: a pigment forming from about 6 percent by weight to about 35 percent by weight of tHe total mixture.
 4. The powder coating composition of claim 3 further comprising: a small weight percentage of an antistatic agent.
 5. The powder coating composition of claim 2 wherein: said diphenol is selected from the group consisting of Bisphenol A, dihydroxy diphenyl sulfone, 1,1''-bis (4-hydroxyphenyl) cyclohexane, 2,2''-biphenol, 4,4''-biphenol, 1,3-dihydroxynaphthalene, bis(2-hydroxyphenol) methane, 4,4''-dihydroxydiphenyl sulfide, 4,4''-dihydroxydiphenyl oxide, bis(4-hydroxyphenyl) methane, and 2,2''-bis(4-hydroxyphenyl) butane.
 6. A powder coating composition comprising a mixture of: A. a copolymer of a glycidyl ester of a mono-ethylenically unsaturated acid and an ethylenically unsaturated compound in such proportions as to obtain a copolymer with a glass transition temperature in the range of 50*C to 80*C and a molecular weight (Mn) in the range of 3,000 to 6,500, said glycidyl ester being present in the copolymer from at least about 10 percent by weight to no more than about 20 percent by weight; B. a diphenol selected from the group consisting of Bisphenol A, dihydroxy diphenyl sulfone, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2''-biphenol, 4,4''-biphenol, 1,3-dihydroxynaphthalene, bis (2-hydroxyphenyl) methane, 4,4''-dihydroxydiphenyl sulfide, 4,4''-dihydroxydiphenyl oxide, bis (4-hydroxyphenyl) methane, and 2,2''-bis (4-hydroxyphenyl) butane, said diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer; C. a flow control agent forming from at least about 0.05 percent to about 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (Mn) of at least 1,000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and D. a small weight percentage of a catalyst which produces a gel time for the powder coating composition at the compositions baking temperature of at least 1 minute and no greater than 40 minutes.
 7. The powder coating composition of claim 6 further including: a pigment forming from about 6 percent by weight to about 35% by weight of the total mixture.
 8. The powder coating composition of claim 7 further including: a small weight percentage of an antistatic agent.
 9. The powder coating composition of claim 6 wherein: said diphenol is selected from the group consisting of Bisphenol A, dihydroxydiphenyl sulfone, bis(2-hydroxyphenyl) methane, and 2, 2''-bis(4-hydroxyphenyl) butane.
 10. A powder coating composition comprising a mixture of: A. a copolymer of a glycidyl ester of a mono-ethylenically unsaturated acid and an ethylenically unsaturated compound in such proportions as to obtain a copolymer which a glass transition temperature in the range of 60*C to 70*C and with a molecular weight (Mn) in the range of 3,000 to 4,000, sai glycidyl ester being present in the copolymer from at least about 12 percent by weight to no more than about 18 percent by weight; B. a diphenol selected from the group consisting of Bisphenol A, dihydroxy diphenyl sulfone, 1,1''-bis(4-hydroxyphenyl) cyclohexane, 2,2''-biphenol, 4,4''-biphenol, 1,3-dihydroxynaphthalene, bis(2-hydroxyphenyl) methane, 4,4''-dihydoxydiphenyl sulfide, 4,4''-dihydroxydiphenyl oxide, bis(4-hydroxyphenyl) methane, and 2,2''-bis(hydroxyphenyl) butane, said diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer; C. a flow control agent forming from at least 0.05 percent to 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (Mn) of at least 1, 000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and D. a small weight percentage of a catalyst which produces a gel time for the coating composition at its baking temperature of at least 1 minute and no greater than 10 minutes.
 11. The powder coating composition of claim 10 wherein: a pigment is included which forms from about 6 percent by weight to about 35% by weight of the total mixture.
 12. The powder coating composition of claim 11 further including: a small weight percentage of an antistatic agent.
 13. The powder coating composition of claim 10 wherein: said diphenol is selected from the group consisting of Bisphenol A and dihydroxydiphenyl sulfone.
 14. A powder coating composition comprising a mixture of: A. a copolymer of a glycidyl ester of a mono-ethylenically unsaturated acid and (1) an ethylenically unsatured monomer selected from the group consisting of methyl methacrylate, butyl methacrylate, butyl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate; and (2) a modifying monomer selected from the group consisting of styrene, alpha methyl styrene, acrylonitrile and methacrylonitrile, in such proportions as to obtain a copolymer having a glass transition temperature in the range of 40*C to 90*C and a molecular weight (Mn) in the range of 2,500 to 8,500, said glycidyl ester being present in the copolymer from at least about 8 percent by weight to no more than 25 percent by weight, said modifying monomer being present in the copolymer from 0 percent by weight to no more than about 35 percent by weight; B. a diphenol having a molecular weight in the range of about 110 to 550, said diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer; C. a flow control agent forming from at least 0.05 percent to 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (Mn) of at least 1000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and D. a small weight percentage of a catalyst which results in a gel time for the powder coating composition at its baking temperature of at least 1 minute but no greater than 40 minutes.
 15. The powder coating composition of claim 14 wherein: a pigment is included which forms from about 6 percent by weight to about 35 percent by weight of the total mixture of the powder caoting composition.
 16. The powder coating composition of claim 15 wherein: a small weight percentage of an antistatic agent is added.
 17. The powder coating composition of claim 14 wherein: said diphenol is selected from the group consisting of Bisphenol A, dihydroxy diphenyl sulfone, 1,1''-bis(4-hydroxyphenyl) cyclohexane, 2,2''-biphenol, 4,4''-biphenol, 1,3-dihydroxynaphthalene, bis(2-hydroxyphenyl) methane, 4,4''-dihydroxy diphenyl sulfide, 4,4''-dihydroxydiphenyl oxide, bis (4-hydroxyphenyl) methane, and 2,2''-bis(4-hydroxyphenyl) butane.
 18. A powder coating composition comprising a mixture of: A. a copolymer of a glycidyl ester of a mono-ethylenically unsaturated acid and (1) an ethylenically unsaturated monomer selected from the group consisting of methyl methacrylate, butyl methacrylate, butYl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate, and (2) a modifying monomer selected from the group consisting of styrene, alpha methyl styrene, acrylonitrile and methacrylonitrile in such proportions as to obtain a copolymer having a glass transition temperature in the range of 50*C to 80*C and a molecular weight (Mn) in the range of 3,000 to 6,500, said glycidyl ester being present in the copolymer from at least 10 percent by weight to no more than 20 percent by weight, said modifying monomer being present in said copolymer from 0 percent by weight to no more than about 35 percent by weight; and B. a diphenol selected from the group consisting of Bisphenol A, dihydroxy diphenyl sulfone, 1,1''-bis(4-hydroxyphenyl) cyclohexane, 2,2''-biphenol, 4,4''-biphenol, 1,3-dihydroxynaphthalene, bis (2-hydroxyphenyl) methane, 4,4-dihydroxydiphenyl sulfide, 4,4''-dihydroxydiphenyl oxide, bis(4-hydroxyphenyl) methane, and 2,2''-bis(hydroxyphenyl) butane, said diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxy groups for each epoxy group in the copolymer; C. a flow control agent forming from at least about 0.05 percent to 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (Mn) of at least 1,000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and D. a small weight percentage of a catalyst sufficient to produce a gel time for the powder coating composition at its baking temperature of at least 1 minute but no greater than 40 minutes.
 19. The powder coating composition of claim 18 wherein: a pigment is included which forms about 6 percent by weight to about 35 percent by weight of the total mixture of the powder coating composition.
 20. The powder coating composition of claim 19 wherein: a small weight percentage of antistatic agent is added.
 21. The powder coating composition of claim 18 wherein: said diphenol is selected from the group consisting of Bisphenol A, dihydroxydiphenyl sulfone, bis(4-hydroxyphenyl) methane and 2,2''-bis(4-hydroxyphenyl) butane.
 22. A powder coating composition comprising a mixture of: A. a copolymer of a glycidyl ester of a mono-ethylenically unsaturated acid and (1) an ethylenically unsaturated monomer selected from the group consisting of methyl methacrylate, butyl methacrylate, butyl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate, and (2) a modifying monomer selected from the group consisting of styrene, alpha methyl styrene, acrylonitrile and and methacrylonitrile in such proportions as to obtain a copolymer having a glass transition temperature in the range of 60*C to 70*C and a molecular weight (Mn) in the range of 3,000 to 4,000, said glycidyl ester being present in the copolymer from at least about 12 percent by weight to no more than 18 percent by weight, said modifying monomer being present in said copolymer from 0 percent by weight to no more than about 25 percent by weight; and B. a diphenol selected from the group consisting of Bisphenol A, dihydroxy diphenyl sulfone, 1,1'' bis(4-hydroxyphenyl) cyclohexane, 2,2''-biphenol, 4,4''-biphenol, 1,3-dihydroxynaphthalene, bis(2-hydroxyphenyl) methane, 4,4''-dihydroxydiphenyl sulfide, 4,4''-dihydroxydiphenyl oxide, bis(4-hydroxyphenyl) methane, and 2,2''-bis(4-hydroxyphenyl) butane, said diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer; C. A flow control agent forming from at least about 0.05 percent to 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular mixture (Mn) of at least 1,000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and D. a small weight percentage of a catalyst sufficient to produce a gel time for the powder coating composition at its baking temperature of at least 1 minute but no greater than 10 minutes.
 23. The powder coating composition of claim 22 wherein: a pigment is included which forms about 6 percent by weight to about 35 percent by weight of the total mixture.
 24. The powder coating composition of claim 23 wherein: a small weight percentage of an antistatic agent is added.
 25. The powder coating composition of claim 22 wherein: said diphenol is selected from the group consisting of Bisphenol A, dihydroxydiphenyl sulfone, bis(4-hydroxyphenyl) methane and 2,2''-bis(4-hydroxyphenyl) butane.
 26. The powder coating composition of claim 23 wherein: said mixture forming said powder coating composition has a particle size in the range from 10 microns to 100 microns.
 27. The powder coating composition of claim 23 wherein: the size range of the particles forming the powder coating composition is in the range of 40 to 75 microns.
 28. A powder coating composition comprising a mixture of: A. a copolymer of a glycidyl ester of a mono-ethylenically unsaturated acid and (1) an ethylenically unsaturated monomer selected from the group consisting of methyl methacrylate, butyl methacrylate, butyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate, and (2) a modifying monomer selected from the group consisting of styrene, alpha methyl styrene, acrylonitrile and methacrylonitrile in such proportions as to obtain a copolymer having a glass transition temperature in the range of 60C to 70*C and a molecular weight (Mn) in the range of 3,000 to 4,000, said glycidyl ester being present in the copolymer in the rnage of 12 to 15 percent by weight, said modifying monomer being present in said copolymer from 0 percent by weight to no more than 35 percent by weight; and B. a diphenol selected from the group consisting of Bisphenol A and dihydroxyphenyl sulfone in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer; C. a flow control agent forming at least about 0.05 percent to 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (Mn) of at least 1, 000, said flow control agent being a polymer or a copolymer selected from the group consisting of acylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and D. a small weight percentage of a catalyst which gives to the mixture a gel time at its baking temperature of at least 3 minutes but not in excess of 10 minutes.
 29. The powder coating composition as defined in claim 28 wherein: 6 percent to 35 percent by weight of the mixture is made up of a pigment.
 30. A powder coating composition comprising a mixture of: A. a copolymer of glycidyl methacrylate, methyl methacrylate and butyl methacrylate, said glycidyl methacrylate being present in the copolymer from about 8 percent by weight to no more than about 25 percent by weight, said methyl methacrylate being present in the copolymer from about 15 percent by weight to about 52 percent by weight, with the balance of the copolymer being said butyl methacrylate, the copolymer having a glass transition temperature in the range of 40* C to 90*C and a molecular weight (Mn) in the range of 2,500 to 8,500; B. a diphenol having a molecular weight of 110 to 550, said diphenol being present in the amount of 0.8 to 1.1 phenolic hydroxyl groups for each epoxy group in the copolymer; C. a flow control agent forming from at least 0.05 percent to 4.0 percent by weight of the mixture, said flow control agent being a polymer having a molecular weight (Mn) of at least 1, 000, said flow control agent being a polymer or a copolymer selected from the group consisting of acrylate esters, methacrylate esters and polyethylene or polypropylene glycol esters of fluorinated fatty acids; and D. a small weight percentage of a catalyst sufficient to cause the coating composition mixture to have a gel time of at least 1 minute but no greater than 40 minutes.
 31. The powder coating composition of claim 30 wherein: 6 percent to 35 percent by weight of the mixture is a pigment. 